Simulation of interference effects in particle streams following impact with a fiat surface Part II. Parametric study and implications for erosion testing and blast cleaning

In a companion paper [Simulation of interference effects in particle streams following impact with a flat surface. Part I. Theory and analysis, submitted for publication], a computer simulation capable of describing the interference between an incident stream of spheres and those rebounding from a flat surface was presented. In the present paper, the model is used to study the effect of the following parameters on the severity of inter-particle collisions: stream angle of incidence, nozzle divergence angle, incident particle velocity, particle size, particle flux, particle-particle and particle-surface impact parameters, and standoff distance. Useful dimensionless parameters are identified and their significance is characterised using a sensitivity analysis. A detailed parametric study of the most important input parameters revealed that interference effects strongly depend not only on flux, but also on angle of attack, standoff distance, coefficient of restitution between particle and surface, and nozzle to particle radius ratio. It is thus important that a full description of experimental conditions in erosion tests be given. Finally, a series of non-dimensional results was presented that can be used to assess the reduction, due to interference effects, in stream power from that available at the nozzle exit. This can be used to estimate how coverage in shot peening, and erosive power in erosion testing, will be affected by interference effects. (C) 2003 Elsevier Science B.V. All rights reserved.